Self-adjusting mandrel or implement holder



Oct. 3, 1944. BAUR SELF-ADJUSTING MANDREL OR IMPLEMENT HOLDER Filed NOV. 5, 1943 FIG/Z.

FIG.\;

glwwm R u A B un D N 0 M M DR am n s Patented Oct. 3, 1944 SELF-ADJUSTING MANDREL OR IIVIPLEMEN T HOLDER Raymond H. Baur, Miami Beach, Fla.

Application November 5, 1943, Serial No. 509,105

9 Claims.

The invention relates to a self-adjustable ma'ndrel or implement holder and more particularly such a device intended to be driven from any suitable and convenient source of power to impart to an associated implement a rotatable and yieldable operation.

Primarily the device is intended for the purpose of sanding, cutting or in any way displacing facing material as in working over the surface of a member to be abraded, smoothed or polished, and in the operation of which it is desirable that the propelling shaft or handle may occupy various angles relative to the work, or the work, as a whole, may be inclined relative to the operating shaft or changed inclinations during the working of the implement.

The invention embraces the ancillary objects of providing an implement adapted to be driven through a suitable connection with an automatic electric drill or the like and possessing a head or reinforcing backing member carrying a treating material, such as sandpaper and means connecting the head to a driven shaft in such a way as to have the head rotated from the axis of said shaft with an interposed yieldable member between the driven shaft and head, permitting one to yield relative to the other at inclinations within the limits of an elastic instrumentality disposed about the shaft and interposed between an abutment thereon and the face of the said head whereby either the shaft or handle may change from a truly right angular normal position of the shaft Withreference to the head, or the head may change from a truly horizontal position with reference to the axis of the shaft, to an inclined relationship according to the surface of the work being treated. I

The invention still further embraces the objects of having the means, constituting the connection between the operating shaft and head, of yieldable or cushioning character to maintain the parts in relatively firm or stable relationship, save as conditions force the modified relationship to create the .angularity referred to, to compensate for conditions attending the working of the implement; also means whereby the firmness of said yieldable means may be adjusted to suit the ends desired, attending specific work, and. means whereby the same will be maintained in predetermined adjusted condition Without-liability of the rotation of the implementhaving a tendency to unfasten or impair the normal adjustment. v I

I have illustrated in the accompanying drawings, and will describe" in detail, the preferred @11 bodiments of the invention, it being understood that the construction and arrangement of parts thus disclosed may be subject to change that may be within the terms or the scope of the hereto appended claims.

Referring to the drawing:

Figure 1 is a top view of one embodiment.

Figure 2 is a side elevation thereof.

Figure 3 is a vertical sectional view thereof.

Figure 4 is a perspective view of an elastic ring constituting part of the adjustable yielding connection interposed between the driving and driven parts of the device; and

Figure 5 is a side elevation of another embodiment of the invention.

Referring more specifically to the drawing, wherein like reference numerals designate the same parts in the several views, 6 represents a shaft which may be regarded as the driven shaft of an electric drill or the like, or a supplemental extension intended to be coupled to said shaft in any convenient manner for rotation by the latter. 1 is a backing plate or head against which is secured sandpaper or other treating material 8, in frictional engagement with the bottom of an interposed yieldable member 9,. fastened to the bottom face of the backing plate, to relieve some of the harshness of the tool against the surface of the work being treated. It is preferable that the cushioning member 9 be permanently attached to the head 1 and the sandpaper 8 held by frictional engagement with the rubber of the cushioning member 9. The backing, plate or head 1, cushioning member 9 and sandpaper sheet are all preferably of circular contour and have registering central openings l 0, I l and I2, through which the lower end of the shaft 6 extends, said opening ID in the head 1, being somewhat larger than the aligned opening I2 in the cushioning member 9 and the opening II in the member 8 being also somewhat larger than the opening I2 in the cushioning member 9, so that the shaft may have an angular movement relatively unimpeded by the members 1 and 8 and cushioned by the edge of the cushioning member 9, surrounding and abutting the adjoining portion of the shaft 6, passing therethrough. In order that the working member, embodying the members 1, 8 and 9, may be secured to rotate with the shaft 6 the latter is provided with an enlargedhead l3, the upper surface and edge of which is of rounded contour so that when the shaft and its head is drawn upwardly in fastening theparts together, as soon to be described, the center portion of the sandpaper sheet 8 may be drawn upwardly or deflected to coincide with the normally as illustrated in Fig. 3, to create an offset or bend therein as indicated at I4, to assist in binding the parts together whereby the rotation thereof is assured. A rubber ring I5 of substantial height, and of a diameter to surround the shaft 6 with ample space I6 between the ring and shaft, is adapted at its lower edge I! to bear upon the backing 'plate or head I immediately-adjacent to the shoulder I8, of the offset I4, previously referred to, whereby a strong binding is created for the working implement I, 8 and 9 when the head I3, of the shaft 6, is drawn upwardly and the compressible ring I5 is forced downwardly in opposition thereto.

' ing agent I5 constitutes a firm gripping instru- A follower I9, in the nature of a disc having a cut-out circumferential portion 20, and providing a circular shoulder 2|, conforming to the upper edge portion of the ring I5, is loosely fitted over the shaft 6 and the nut 22 engaging a threaded portion 23 on the shaft, is adapted to bear on the rounded upper face 24 of the follower I9. It willbe seen that as the nut 22 is forced downwardly by the threaded engagement with the correspondingly threaded portion 23 of the shaft, the same will exert a force against the said rounded surface 24 of the follower I9, and through the latter compress longitudinally to the desired extent, the rubber or equivalent ring I5 thus binding the working element 1, 8 and 9, in its deflected or offset middle portion between the bottom edge of the ring I5 and the upper surface of the head I3 of the shaft 6.

There is some play, of course, between the bore 25 of the follower I9 to. avoid the threaded portion 23 of the shaft 6. w I

, Preferably the head or backing plate 1 is of slightly curved or dished formation so that the outer edge thereof, and incidentally the outer or peripheral edges of the yieldable backing 9 and sandpaper or equivalent 8 are deflected upwardly to avoid sharp or scraping underedges on the device facing the work. 7 p

It is desirable that the paper or disc 8, in contact with the backing 9, extends slightly beyond the peripheral edge of the backing plate I and the. backing 9 so that in working into corners or.sides the working edges of the sandpaper 8 may have contact with the'workto the fullest extent, the sandpaper or equivalent 8 being normally in a fiat plane due to centrifugal force.

From the foregoing detail description it will be apparent that in a normal operation and in treating truly horizontal or plane surfaces, the setup of the implement is with the plane of the parts I, '8 and 9 and the axis of the shaft 6 at truly right angles, but as the position of the work, with reference to the tool, especially in instances of hand tools are such as to require, a relative adjustment or where the surfaces of the work being treated will vary so as to render it necessary or expedient to have the shaft and working member 1, 8 and 9, or. its equivalent, angularly adjust themselves relative to their normal or rigid adjustment, the driving and driven elementseof the. V implement may angularly adjust relative to each other, as suggested bythe illustration in dotted 7 lines in Fig. 3 of'the drawing at which time the operate after the fashion of a universal joint;

also that the arrangement avoids setting up any substantial vibration or impairment of the desired concentric arrangement of the driven parts with reference to the propelling shaft. By the arrangement illustrated I obtain somewhat universal action under any expedient or condition. There remains but one feature to further refer to, very important from a maintenance of operation standpoint, and it is this:

So far as I am aware it has always been customary when combining a driving shaft, which is clockwise in its rotation, to secure interfitting members by nuts having corresponding right hand threads engaging complemental threads, which results in a tendency, during the operation of the tool, to loosen by movement and incidently the parts originally bound thereby. To obtain relief from the disadvantage referred to, resort had to be made to lock nuts or securing devices of various sorts. In my construction '1 form the nut with left hand threads and have the threads on the threaded portion. 23 of the shaft of a complemental character so that after the nut is screwed homein a left direction and the parts bound together, the operation of the tool in the customary clockwise rotary movement cannot have a tendency to loosen the operative engagement but will rather have a tendency to make the same more secure. I regard this as an almost critical feature of my combination so far as a permanent operable I of the invention, other than the one already de-' scribed in the other figures of the drawing. The same comprises, in the main, the substitution of a coiled spring metal yieldable and cushioning device between the follower on the drive shaft and the back of the immediate work-treating implement. In this modified or alternative arrangement, and referring, of course, to Figure 5, 26 is the driving. shaft for the implement 21, the latter having a suitable work face and backing plate 28 with the cushioning material 29 therebetween, as heretofore understood, through which the shaft 26 passes, said shaft having a head 38 to underlie the raised central portion of the combined implement 21, 28 and 29 whereby to bind 5 r the implement for rotation, and against displacement, between the upper surface of the head 30 and the lower convolution of the spring 3| disposed around the shaft 26 and spaced, more so at its lower end, from the shaft so that said lower convolution of the spring abuts the upper surface of th backing plate 28 of the implement as at 32, beyond the periphery of the head 30 and substan tially in the plane of the under surface of the latter so that the offset'central portion of the implement 21, 28 and 29may be firmly bound therebetween with thehead of the shaft 26 substantially above the plane of the underworking face of the implement when in contact with the work. The coiled springv i's'of somewhat conical or tapering outline, the diameter of. which decreases gradually in an upward direction to the upper end coil 33 thereof; so that it engages the under surface of a follower-nut 34, adjustable along a left hand threaded portion 35 of the shaft ity for purposes hereinbefore outlined-in other words, the feeding of theleft hand threaded nut 34 downwardly over th threaded portion 35 of the shaft 26 compresses the spring to the desired extent to firmly hold the shaft'and implement together under the determined pressure, without any tendency to loosen the follower-nut 34 under the clockwise operating. rotation of the implement; and the freedom of lateral movement between the follower-nut 34 and spring, and deflectability of the spring between the follower-nut and the implement will permit of the relative angular adjustment laterally of the normal right angular relationship between the axis of the shaft and the normal plane of the implement.

At 36 I have shown a ring or flange, or equivr alent lug, projecting upwardly from the face of the backing plate 28 of the implement, and withg in the lowermost coil 32 of the spring, to keep the latter concentric with the shaft and prevent undue shifting of the lower bearing portion of the spring under the influence of the changing angular relationships between the operating shaft and implement.

I claim:

1. The combination with an abrading or similar implement having, a work-treating portion and an offset central portion, of means for securing the same for rotation, comprising a driving shaft passing through said offset portion and holding the same against outward movement but permitting the shaft to axially tilt and change its angular relationship to said work-treating portion, an elongated radially flexible rubber ring surrounding the shaft engaging at its lower end with the surface of the implement beyond said offset portion to bind the implement between the shaft and ring, a follower loose on the shaft in engagement with the opposite end of the ring, and means threaded to the shaft for forcing the follower thereover to compress the ring substanr tially as described.

2. The combination with an abrading or similar implement having a work-treatin portion and an offset central portion, of means for securing the same for rotation, comprising a driving shaft connected to said work-treating portion for universal adjustment relative to the working plane of said portion, an elongated radially flexible rubber ring surrounding the shaft engaging at its lower end with th back of the implement, a follower on the shaft in engagement with the opposite end of the ring, and means associated with the follower for creating pressure on the ring whereby a binding action to hold the implement 'between the shaft and ring is effected.

3. The combination with an abrading or similar implement having a work-treating portion and an offset central portion, of means for securing the same for rotation, comprising a driving shaft, an elongated radially flexible rubber ring surrounding the shaft engaging at its lower end with the back of the implement, a follower on the shaft in engagement with the opposite end of the ring, and means associated with the follower for creating pressure on the ring whereby a binding action tohold the implement between the shaft and ring is effected, the engagement betweenthe 'shaft and implementand between the rubber ring and follower being such' as to permit the shaft and implement to occupy relatively different angularities as permitted by the deflection and bend of the ring.

4. An implement holder of the character described comprising a driving shaft, a rubber ring surrounding the same and spaced therefrom, the shaft having provision to engage an abrading implement or the like to bind the samebetween the shaft and ring while permitting the shaft to tilt, a follower on the shaft in engagement with one end of the ring, and means for adjusting the follower on the shaft'to compress the ring to grip'the implement, the-rubber ring being of substantial thickness to render the same stable when normally concentric to the shaft but permitting lateral elasticity to adjust the angular relation between the shaft and implement to accommodate irregularities of the surface being treated or angular relation of the shaft with the surface of said work.

5. An adjustable implement holder of the character described, comprising a driving shaft having a headed lower end engaging beneath said implement and a rigid stem portion extending from the head through the implement, and spring means surrounding the shaft and spaced therefrom resilient in directions axially and radially of the shaft, engageable at one end with the surface of the implement and at the other end operatively associated with the shaft, whereby the shaft may axially assumesdifferent angular relationships with the implement in all radial directions described from the engaged headed end of the stem portion.

6. An adjustable implement holder of the character described, comprising a driving shaft having a headed lower end engaging beneath said implement and a rigid stem portion extending fro-m the head through the implement, and a spring cushioning rin entirely surrounding the shaft and spaced therefrom resilient in directions axially and radially of the shaft, engageable at one end with the surface of the implement and at the other end operatively associated with the shaft, whereby the shaft may axially assume different angular relationships with the implement in all radial directions described from the engaged headed end of the stem portion.

'7. An implement of the character described comprising a driving shaft having a headed lower end engaging beneath said implement and a rigid stem portion extending from the head through the implement, a yieldable and compressible radially resilient cylindrical member surrounding the shaft within which the shaft may assume different angular relationships with the implement in all radial directions described from the engaged headed end of the stem portion, an abrading or similar device adapted to be secured in binding relationship between a part on the shaft and the adjacent end of said member, a follower on the shaft in engagement with the other end of said member, and means for adjusting said follower including a left hand threaded engagement with the shaft to bind the parts together in opposition to the clockwise rotation of the same in operation.

8. The combination with an abrading or similar implement having a work-treating portion and an offset central portion, of means for securing the same for rotation, comprising a driving shaft, an elongated radially resilient rubber ring surrounding the shaft engaging at its lower end with the back of the implement, a follower on the shaft in engagement with the opposite end of the ring, and means associated with the follower for creating pressure on the ring whereby a binding action to hold the implement between the shaft and ring is effected, said last-mentioned means comprising a left hand threaded engagement between the adjusting means for the foL lower and thershaft. V

9. The combination with an abrading or similar implement having arwork-treating portion and an offset central portion, of means for yieldably securing the same for rotation, comprising a driving shaft having a headed lower end engaging beneath said implement and a rigid stem plement, a follower on the shaft in engagement with the opposite end of the elongated eam. pressibleand deflectable'means, and means associated with the follower for creating pressure on the ring whereby a binding "action'to hold the implement between the same and shaft is effected.

RAYMOND H. 'BAUR. 

